Refillable fuse



S. W. FARNSWORTH.

REFILLABLE FUSE.

APPLICATION man luNEzx, 191e.

Ze/BWM Y ATroRNEY Patented Oct. 17, 1922,

UNITED STATES SIDNEY W. FARNSWORTH, OF CHICAGO,

ILLINOIS, ASSIGNOR T0 WESTING-HOUSE ELECTRIC & MANUFACTURING COMPANY, ACORPORATION 0F PENNSYLVANIA.

REFILLABLE rusia Application nica :une 2i,

To all whom it may concern.'

Be it known that I, SIDNEY- W. FARNB- WORTH, a citizen of the UnitedStates, and a resident of Chicago, inthe county of Cook and State ofIllinois, have invented a new and useful Improvement in RefillableFuses, of which the following is a specification.

My invention relates to fuses and particularly to fuses of the rellabletype.

One object of my invention is to provide a refillable fuse in which thepermanent conducting parts shall be prevented from becoming coated withoxides resulting from repeated operation of the fusible elements of thesaine. f

Another object of my invention is to provide a fuse that shallcompriselpermanent 'members and a plurality of fusible elementsseverally disposed in renewable auxiliary receptacles.

A further object of my invention is to provide a fuse that shall beruptured at a plurality of points to reducethe violence of the attendantexplosion.

A still further object of my invention is to prevent burning of theinsulation of refillable fuses in which re eated operation is likely toresult in the ormation of relatively fi'ee paths between the arc flameand surrounding bodies.

Heretofore, refillable fuses have usually been constructed of insulatingtubing, to the ends of which terminal members have been screw-threadedor otherwise attached and in which there has been free communicationbetween the fusible elements and the terminal members or otherconducting parts.

vThis construction permitted the `accumulation of oxides upon thepermanent conducting members to which the fusible elements wereattached, with the result that, after a relatively few operations, theadded resistance of the circuit was of such value as to abnormally heatthe elements and thereby cause them to be ruptured at current valuesmuch below that at which they were designed to operate. Further, therepeated passage of flame between the terminal cap threads .or otherspacesv between the caps and the insulatin receptacles vey oftenburnedaway a su cient quantity o the insulating material to establishdangerous fire paths to surrounding bodies.

In Opracticing my invention, I so segregate 1918. Cerial No. 241,258.

a plurality of renewable fusible elements from the permanent parts of afuse device, by enclosing the -saine in auxiliary renewa le receptacles,as to prevent the accumulation ofoxides upon the conducting parts andthe burning of the insulating material thereof.

The single figure is a view, partiallyl in terminal members 4 extend,and inwardly projecting flanges 5 which have overlapping engagement withoutwardly projecting flanges 6 upon the members 4 to hold the latter inposition. v

A cylin rical conducting member 7, ref,- erably of copper, but which maybe 0 any other suitable material, is concentrically disposed within themember 1 and extends substantially equal distances longitudinally fromthe center of the member 1.- Auxiliary receptacles 8 comprisingdiscoidal end plates 9, of copper or other suitable material, and hollowcylindrical sidewalls 10, of fiber or other suitable insulatingsubstance, are disposed between the ends of the member 7 and the innerends of the mem-bers 4. The terminal members 4, receptacles 8 and themember 7 are placed in "rigid co-axial relation in the receptacle l byproperly screwing the cap members 2 thereon. Fusible elements 11 aredisposed within the auxiliary receptacles 8 andl extend between theplates 9 to which they may be secured in any suitable manner. Aconducting path through the device is provided from the terminal members4 through the plates 9, elements 11 and the member 7. Holes 12 and 13may be provided in the plates 9 and in the parts 1 and 7, respectively,to permit `the escape of arc gases.

When a short circuit occurs, the elements 11, being in series relationand of the same cross-sectional area, are ruptured simultaneously,thereby doubling the counterelectromotive force in the circuit andreducing the explosive force caused bythe arc. A smally or graduallyincreasing overload may cause but one of the elements 11 to be ruptured,thus necessitating the renewal of but one of the same. inasmuch as thefusible elements are enclosed in auxiliary receptacles, that arereplaced new ones after each opeiation, accumulation of oxides on thepermanent conducting parts of the device and the burning of thepermanent insulating parts are avoided. -In this manner, the eiliciencyof the device is maintained bv reason of the fact that the fusibleelements are ruptured at the current value for which they are designed,and the danger from fire to surrounding bodies is eliminated.

While I have shown and described a particular form of my invention, manychanges mav he made therein without departing froin the spirit and scopethereof, as set forth in the appended claims.

I claim as my invention:

l. The combination with a unita-ry fuse structure comprising areceptacle and terminal members closing the ends thereof, of a fuseelement comprising a plurality of alternately disposed unattachedseries-related fusible and normally non-fusible members extendingbetween said terminal members in said receptacle, said element beingrupturable at a plurality of places simultaneously.

2. The combination with a unitary fuse structure comprising a mainreceptacle and terminal members closing the ends thereof, of a pluralityof enclosed auxiliary cartridge fuse receptacles disposed in said mainreceptacle and connected in circuit relation to said terminal members.

8. The combination with an enclosed fuse structure comprising aninsulating receptacle and terminal members,substantially closing theends thereof, of a conducting member disposed at an intermediateposition in said receptacle, and a removable unattached fuse elementdisposed between each of said terminal members and said conductingmember.

4. The combination with an enclosed .fuse structure comprising a hollowcylindrical insulating receptacle and main terminal members disposed atthe ends thereof, of a hollow cylindrical conducting member centrallydisposed in said receptacle and two renewable fuse elements eachdisposed between, and engaging, one end of said conducting member andlone of said terminal members, each of said renewable fuse elementscomprising an insulating receptacle, auxiliary terminal members closingthe ends thereof and a fusible member disposed therein and engaging saidauxiliary terminal members.

5. In a fuse device, the combination with a plurality ofindependentcartridge fuse structures each comprising a tubularreceptacle and terminal members closing the ends thereof, of means forsupporting said structures in end-to-end relation to constitute a singlefuse device having a plurality of fusing points.

6. In a cartridge fuse device, the combination with a main receptacleand terminal members closing the ends thereof, of a plurality ofauxiliary cartridge fuse devices, each comprising a receptacle andterminal members closing the ends thereof, disposed in end-to-endrelation between the terminal members of said main receptacle.

7. In a cartridge fuse device, the combination with a. main receptacleand terminal members closing the ends thereof, of a plurality ofauxiliary cartridge fuse de vices, each comprising a receptacle andterminal members, disposed in spaced series relation vbetween theterminal members of said main receptacle, and means for operativelyconnecting said auxiliary devices.

8. The combination with a unitary fuse structure comprising a tubularreceptacle and terminal members closing the ends, of a plurality ofunattached fuse elements disposed within tlie receptacle and held inconluctive relation between the terminal meiners.

9. The combination with a unitary fuse structure comprising a receptacleand terminal members associated therewith, of a plurality of unattachedfuse elements disposed within the receptacle and held in conductiverelation by the terminal members.

l0. The combination with a unitary fuse structure comprising areceptacle and terminal members associated therewith at least one ofwhich is adjustable, of a plurality of uiiattached fuse elementsdisposed within the receptacle and adapted to be clamped in 1onductiverelation by the terminal meiners.

l1. The combination with a unitary fuse structure compising a receptacleand terminal members associated therewith, of a fuse element comprisinga plurality of unattached fusible and normally non-fusiblemembersldisposed between the said terminals and thereby held inconductive relation.

In testimony whereof, I have hereunto subscribed my name this 7 day ofJan. 1920.

SIDNEY W. F ARNSWORTH.

